This research is aimed at the elucidation of the dynamics and structural processes involved in homogeneous nucleation. Despite the long history of research in this area, little is known about the metastable states of matter. In the first year of this grant, we have made significant progress towards understanding these phenomena using computer simulation techniques. We have now an accurate view of the structure of the interface between liquid nuclei and gases. In this second year of the grant, we propose to gain a quantitative understanding of the thermodynamics and kinetics of nucleation by extending our molecular dynamics work. In an entirely different sphere, we propose to conclude our studies of molecular hydrodynamics by determining how hydrodynamic boundary conditions are related to the intermolecular forces between molecules. In addition, we shall try to explain theoretically the empirical observation that in protein solutions, the tumbling of the water molecules contains information about the tumbling of the protein molecules. In yet another area, we will investigate the structure and kinetics of dypeptide bonds in aqueous solution. This will be done by applying Monte Carlo and Brownian molecular dynamics techniques to the Stillinger II potential. This is an outgrowth of work already in progress on the potential of mean force between two hydrophic particles. Lastly, we have made important progress in understanding the time dependence of multiple scattering and have learned how to extract the single scattering even from concentrate dispersions. These techniques will now be used to study the dynamics of ordered isoionic dispersions of polystyrenes as well as their electrophoresis. BIBLIOGRAPHIC REFERENCE: B.J. Berne, "Dynamics of Charged Macromolecules in Solution," in Photon Correlation Spectroscopy and Velocimetry, E. H. Cummins and R. Pike, Plenum, New York In press, 1976.